Samuel R. Hall

TL;DR: In this paper, the authors used observations from the April 2008 NASA ARCTAS aircraft campaign to the North American Arctic, interpreted with a global 3D chemical transport model (GEOS-Chem), to better understand the sources and cycling of hydrogen oxide radicals (HOx≡H+OH+peroxy radicals) and their reservoirs (HOy≡HOx+peroxides) in the springtime Arctic atmosphere.

TL;DR: In this article, the authors measured the mixing ratios and total reactivity of HO2 and OH during the mid-summer 1999 SOS campaign in Nashville, Tennessee, and found that HO2 was greater than expected during daytime when NO mixing ratios were high; ozone production did not decrease as expected when NO was higher than 2 ppbv.

TL;DR: It is demonstrated here that dramatic changes in toxin composition do occur in one isolate of Alexandrium fundyense, and in nitrogen- and phosphorus-limited semi-continuous cultures, toxin composition varied systematically with growth rate.

TL;DR: Evidence is found for rapid recycling of nitric acid to nitrous acid and nitrogen oxides in the clean marine boundary layer via particulate nitrate photolysis through box model calculations based on the Master Chemical Mechanism and laboratory experiments demonstrate thephotolysis of particulates nitrate collected on filters at a rate more than two orders of magnitude greater than that of gaseous nitric Acid.

TL;DR: The first field-based, empirical parameterization of Dinitrogen pentoxide (N2O5) was presented in this paper, which was fit to WINTER data, based on the functional form of previous parameterizations, and showed strong correlation with aerosol water content, but weak correlations with other variables, such as aerosol nitrate and organics.